Information system design is often accomplished through the use of database management systems (DBMS). A DBMS efficiently manages databases, which are shared pools of interrelated data. A DBMS typically provides a data manipulation language (DML), which includes a query language for allowing a user to retrieve and manipulate the data in the database.
Large databases not only provide a means to conveniently store and retrieve data, but also may be used as a decision tool. The collection and examination of large amounts of data can provide a wealth of information with respect to business trends and other business, educational, and scientific decisions. The use of these large databases in this manner typically involves analyses which are very computationally intensive, as various mathematical functions may be performed on a vast amount of data. The use of databases in this manner is often referred to as "decision support".
Due to the great number of computations which may be involved when using database technology as a decision support tool, it becomes clear that processing time may likewise be very high. This can be very undesirable for many reasons. An attempt to make expeditious business decisions can be frustrated where each hypothetical or "what if" query presented to the information system takes hours, or even days, to complete. Furthermore, as computer time carries monetary cost with it, these lengthy computations become prohibitively expensive.
Many of these types of analyses require only an approximate answer, as compared to the very precise answer obtainable by analyzing each and every piece of data. For these cases, only a small portion of the full set of data needs to be processed. As the data portion decreases, so does the computation time.
The present invention provides a method for determining approximate results of database queries, to an accuracy desired by the user. This provides for a decision support tool having the capability to provide very precise, as well as timely results. The present invention therefore provides a solution to the aforementioned problems, and offers other advantages over the prior art.